Sterrekunde

Waarom neem wetenskaplikes aan dat hulle die vorm van die heelal kan meet as dit algemeen beskou word as oneindig?

Waarom neem wetenskaplikes aan dat hulle die vorm van die heelal kan meet as dit algemeen beskou word as oneindig?


We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

Die vorm van die heelal is die vraag of die heelal plat is, positief of negatief is. Onlangs het sterrekundiges bestraling van uiters verre punte van die waarneembare heelal vergelyk en tot die gevolgtrekking gekom dat dit plat is met 'n foutmarge van 0,4%. Op grond van artikels wat ek elders gelees het, blyk dit die konsensus te skep dat die heelal inderdaad is plat. Maar word daar nie geglo dat die heelal ook oneindig groot is nie? As dit regtig oneindig is, moet sulke metings dan nie onbeduidend wees nie, aangesien 'n oneindige geboë heelal vir 'n plaaslike waarnemer nog steeds plat lyk?


Ja, daar word geglo dat die heelal oneindig groot is. Dit is wat u kry as die kromming nul of negatief is, as 'n eenvoudige topologie aanvaar word. Die kromming moet weer positief wees vir 'n eindige heelal, met die veronderstelling van 'n eenvoudige topologie en geen vreemde dinge soos rande nie.

Nou is dit moontlik dat die heelal 'n baie klein positiewe kromming het, sodat dit eindig, maar dit is so groot dat dit vir ons plat lyk.

Dit is egter redelik om aan te neem dat die waarneembare heelal verteenwoordigend is van die hele saak, en nie net toevallig 'n gebied van afwykende kromming nie. Dit is natuurlik onmoontlik om te verifieer, maar as die kromming aansienlik groter was buite ons waarneembare pleister, sou ons verwag dat die kromming 'n bietjie hoër naby die rande sou wees as in die middel van die pleister, en ons sien dit nie in die gegewens.

Maar as die globale kromming is gelyk aan die maksimum positiewe kromming wat ooreenstem met die 0,4% foutmarge van die WMAP-, BOOMERANG- en Planck-data, dan is die krommingsradius van die hele heelal (tans) ongeveer 150 keer groter as die radius van die waarneembare heelal . En natuurlik sal dit voortaan uitbrei.

Die figuur kom uit Hoe groot is die hele heelal? deur die astrofisikus Ethan Siegel. Die artikel het 'n uitstekende verduideliking van die kromming, met baie nuttige diagramme.


As dit regtig oneindig is, moet sulke metings dan nie onbeduidend wees nie, aangesien 'n oneindige geboë heelal vir 'n plaaslike waarnemer nog steeds plat lyk?

Nee, dit sou nie noodwendig nie. Dit kan, maar dit is nie verpligtend nie.

Stel u voor 'n oneindige lyn wat net een of ander tyd skerp draai. Dit sal beslis op daardie stadium 'krom' wees, al is dit oneindig.

Neem 'n parabool. Dit is oneindig, maar het 'n definitiewe kromming in elke punt.

Dieselfde geld vir ons 3D-heelal.


Waarom neem wetenskaplikes aan dat hulle die vorm van die heelal kan meet as dit algemeen beskou word as oneindig?

Want nie almal dink dit is oneindig nie. Kyk na die tydlyn van die oerknal wat Luke Mastin in 2009 geskryf het 'Die lineêre dimensies van die vroeë heelal neem gedurende hierdie periode van 'n klein fraksie van 'n sekonde toe met 'n faktor van ten minste 10$^{26}$ tot ongeveer 10 sentimeter (ongeveer die grootte van 'n pomelo) ”. U kan John Gribbin in sy boek van 2008 sien praat oor 'n heelal so groot soos 'n pomelo Die heelal: 'n biografie. U kan Marcus Chown sien praat oor 'n heelal so groot as 'n pomelo in sy resensie van Alan Guth se boek uit 1997 Die Inflasie Heelal. U kan ook Jeremia Ostriker en Paul Steinhardt sien praat oor 'n heelal van die grootte van 'n pomelo in The Quintessential Universe in SciAm in 2002. Hulle praat nie van die waarneembare heelal nie. Hulle het oor die hele heelal gepraat. En as dit 13,8 miljard jaar gelede die grootte van 'n pomelo was, kan dit nou nie oneindig wees nie.

Die vorm van die heelal is die vraag of die heelal plat is, positief of negatief is. Onlangs het sterrekundiges bestraling van uiters verre punte van die waarneembare heelal vergelyk en tot die gevolgtrekking gekom dat dit plat is met 'n foutmarge van 0,4%.

Dit is reg. Twee uit drie opsies sou altyd verkeerd wees. IMHO as u die Einstein-digitale artikels gelees het, is dit duidelik dat die heelal plat gaan wees. Ja, Einstein het die idee van 'n geslote geboë heelal bedink, sien sy 2de Februarie-poskaart aan Willem de Sitter. Maar teen 1932 het hy en de Sitter die idee laat vaar ten gunste van plat ruimte in hul Einstein-de Sitter-heelal. Kyk na die voorlopige artikel van John Baez en Emory Bunn uit 2006: “Net so is relatiwiteit in die algemeen nie regtig 'n 'krag' nie, maar slegs 'n manifestasie van die kromming van die ruimtetyd. Let wel: nie die kromming van die ruimte nie, maar van die ruimtetyd. Die onderskeid is deurslaggewend ”. Geboë ruimte is nie dieselfde as geboë ruimtetyd nie. Ongelukkig verwar sommige mense die twee.

Op grond van artikels wat ek elders gelees het, blyk dit die konsensus te skep dat die heelal inderdaad plat is.

Ek dink dat die konsensus korrek is.

Maar word daar nie geglo dat die heelal ook oneindig groot is nie?

Baie mense beweer dat 'n plat heelal 'n oneindige heelal moet wees. Maar dit is 'n nie-sequitur. Om weer terug te gaan na Einstein, dink hy aan die ruimte as 'n ding. Daarom het hy in sy opstel oor die geskiedenis van veldteorie in 1929 'n veld beskryf as 'n toestand van ruimte. In sy Nottingham-lesing in 1930 sê hy ruimte “Bly die enigste medium van die werklikheid”. Ek dink dus dat dit redelik is om die heelal as 'n ruimtesfeer te beskou, met geen ruimte daarbuite nie. Miskien sal ligstrale iets soortgelyk aan interne refleksie ondergaan.

As dit regtig oneindig is, moet sulke metings dan nie onbeduidend wees nie, aangesien 'n oneindige geboë heelal vir 'n plaaslike waarnemer nog steeds plat lyk?

Dit is wat sommige mense sê. Maar hulle sê ook dinge soos "die heelal was oneindig ten tye van die oerknal en dit is nou nog oneindiger". Ek hou nie daarvan nie, want dit lyk nie of dit inpas by die Big Bang-kosmologie nie, en ek sien net nie hoe 'n oneindige heelal kan uitbrei nie.


Hoe oud is die heelal?

Ouderdom is miskien net 'n getal, maar wat die ouderdom van die heelal betref, is dit nogal belangrik. Volgens navorsing is die heelal ongeveer 13,8 miljard jaar oud. Hoe het wetenskaplikes vasgestel hoeveel kerse hulle op die verjaardagkoek van die heelal moet sit? Hulle kan die ouderdom van die heelal met behulp van twee verskillende metodes bepaal: deur die oudste voorwerpe in die heelal te bestudeer en te meet hoe vinnig dit uitbrei.


Nuwe Quantum-paradoks openbaar teenstrydigheid tussen wydverspreide oortuigings - "Something's Gotta Give"

Die werklikheid ondersoek van waarnemings deur 'n kunsmatige kwantumintelligensie. Krediet: Kunswerke deur Anthony Dunnigan.

Kwantumfisici aan die Griffith-universiteit het 'n nuwe paradoks onthul wat sê dat, as dit kom by sekere lang oortuigings oor die natuur, 'iets moet gee.'

Kwantumteorie is prakties perfek om die gedrag wat ons waarneem wanneer ons eksperimente op klein voorwerpe soos atome doen, te voorspel. Maar die toepassing van kwantumteorie op skale wat veel groter is as atome, veral waarnemers wat die metings doen, laat moeilike konseptuele probleme ontstaan.

In 'n artikel gepubliseer in Natuurfisika, 'n internasionale span onder leiding van die Griffith Universiteit in Australië, het die kwessies in 'n nuwe paradoks opgeskerp.

"Die paradoks beteken dat as die kwantumteorie werk om waarnemers te beskryf, wetenskaplikes een van die drie gekoesterde aannames oor die wêreld moet prysgee," het mede-professor Eric Cavalcanti, 'n senior teorie-outeur op die blad, gesê.

'Die eerste aanname is dat wanneer 'n meting gemaak word, die waargenome uitkoms 'n werklike, enkele gebeurtenis in die wêreld is. Hierdie aanname sluit byvoorbeeld die idee dat die heelal kan verdeel uit, terwyl verskillende uitkomste in verskillende parallelle heelalle waargeneem word. '

'Die tweede aanname is dat eksperimentele instellings vrylik gekies kan word, sodat ons ewekansige proewe kan uitvoer. En die derde aanname is dat sodra so 'n vrye keuse gemaak word, die invloed daarvan nie vinniger as die lig in die heelal kan versprei nie, 'het hy gesê.

'Elkeen van hierdie fundamentele aannames lyk heeltemal redelik en word algemeen geglo. Daar word egter ook algemeen geglo dat kwantumeksperimente opgeskort kan word tot groter stelsels, selfs tot die vlak van waarnemers. Maar ons wys dat een van hierdie algemene opvattings verkeerd moet wees! Die prysgee van een van hulle het ingrypende gevolge vir ons begrip van die wêreld. ”

Die span het die paradoks vasgestel deur 'n scenario te ontleed met goed geskeide verstrengelde kwantumdeeltjies gekombineer met 'n kwantum 'waarnemer' - 'n kwantumsisteem wat van buite gemanipuleer en gemeet kan word, maar wat self metings op 'n kwantumdeeltjie kan maak.

'Op grond van die drie fundamentele aannames het ons wiskundig beperkings bepaal op die eksperimentele resultate wat in hierdie scenario moontlik is. Maar wanneer die kwantumteorie toegepas word op waarnemers, word die resultate voorspel wat hierdie perke oortree. In werklikheid het ons reeds 'n bewys van die beginsel uitgevoer met behulp van verstrengelde fotone (ligdeeltjies), 'het dr Nora Tischler, 'n senior eksperimentele outeur, gesê. 'En ons het 'n oortreding gevind net soos die kwantumteorie voorspel het.'

'Maar ons' waarnemer 'het so te sê 'n baie klein' brein 'gehad. Dit het net twee geheuetoestande, wat gerealiseer word as twee verskillende weë vir 'n foton. Daarom noem ons dit 'n bewys van beginsel-eksperiment, nie 'n afdoende bewys dat een van die drie fundamentele aannames in ons paradoks verkeerd moet wees nie, 'het sy gesê.

"Vir 'n meer definitiewe implementering van die paradoks, is ons droomeksperiment een waar die kwantumwaarnemer 'n kunsmatige intelligensieprogram op menslike vlak is wat op 'n massiewe kwantumrekenaar werk," het professor Howard Wiseman, die leier van die projek en direkteur van Griffith's Center, gesê. vir Quantum Dynamics, waar die teoretiese en eksperimentele spanne gebaseer is.

'Dit sou 'n redelik oortuigende toets wees of die kwantumteorie vir waarnemers misluk en of een van die drie fundamentele aannames onwaar is. Maar dit is waarskynlik dekades weg. '

Eksperimentele apparaat vir die toets van die paradoks met ligdeeltjies. Krediet: Kok-Wei Bong.

Die Centre for Quantum Dynamics-laboratorium waarin die eksperiment uitgevoer is, is ook deel van die Centre for Quantum Computation and Communication Technology, 'n Australiese sentrum vir uitnemendheid in die navorsingsraad.

"Daar is al lank erken dat kwantumrekenaars 'n rewolusie sal hê in ons vermoë om harde rekenaarprobleme op te los," het professor Wiseman gesê.

"Wat ons nie besef het voordat ons met hierdie navorsing begin het nie, is dat dit ook kan help om harde filosofiese probleme te beantwoord - die aard van die fisiese wêreld, die geesteswêreld en hul verhouding."

Verwysing: & # 8220 'n Sterk no-go-stelling oor die Wigner-vriendeparadoks & # 8221 deur Kok-Wei Bong, Aníbal Utreras-Alarcón, Farzad Ghafari, Yeong-Cherng Liang, Nora Tischler, Eric G. Cavalcanti, Geoff J. Pryde en Howard M. Wiseman, 17 Augustus 2020, Natuurfisika.
DOI: 10.1038 / s41567-020-0990-x


Waarom neem wetenskaplikes aan dat hulle die vorm van die heelal kan meet as dit algemeen beskou word as oneindig? - Sterrekunde

Terwyl Copernicus tereg opgemerk het dat die planete om die son draai, was dit Kepler wat hul wentelbane korrek omskryf het. Op 27-jarige ouderdom word Kepler die assistent van 'n ryk astronoom, Tycho Brahe, wat hom vra om die baan van Mars te definieer. Brahe het 'n leeftyd van astronomiese waarnemings versamel, wat by sy dood in Kepler & rsquos-hande oorgegaan het. (Brahe, wat sy eie aardgerigte model van die heelal gehad het, het die grootste deel van sy waarnemings ten minste gedeeltelik van Kepler weerhou omdat hy nie wou hê dat Kepler dit moes gebruik om die Copernicaanse teorie korrek te bewys nie.) Met behulp van hierdie waarnemings het Kepler bevind dat die wentelbane van die planete het drie wette gevolg.

Soos baie filosowe van sy era, het Kepler 'n mistieke oortuiging gehad dat die sirkel die perfekte vorm van die heelal was en dat die planete en rsquo-bane sirkelvormig moet wees as 'n manifestasie van die goddelike orde. Hy het jare lank gesukkel om Brahe & rsquos-waarnemings van die bewegings van Mars te laat ooreenstem met 'n sirkelbaan.

Uiteindelik het Kepler egter opgemerk dat 'n denkbeeldige lyn wat van 'n planeet na die son getrek is, in gelyke tye 'n gelyke ruimte uitgevee het, ongeag waar die planeet in sy baan was. As u 'n driehoek op een tydstip vanaf die son na 'n planeet & rsquos-posisie teken en die posisie op 'n vasgestelde tyd later & mdashsay, 5 uur of 2 dae & mdash, is die oppervlakte van die driehoek altyd dieselfde, oral in die baan. Om al hierdie driehoeke dieselfde oppervlakte te hê, moet die planeet vinniger beweeg as dit naby die son is, maar stadiger as dit die verste van die son af is.

Hierdie ontdekking (wat die tweede wet van die orbitale beweging van Kepler & rsquos geword het) het gelei tot die besef van wat die eerste wet van Kepler & rsquos geword het: dat die planete in 'n ellips ('n platgetrekte sirkel) beweeg met die son op een fokuspunt, verreken vanaf die middelpunt.

Die derde wet van Kepler & rsquos toon aan dat daar 'n presiese wiskundige verband is tussen 'n planeet en 'n afstand tussen die son en die hoeveelheid tyd wat dit neem om die son draai. Dit was hierdie wet wat Newton geïnspireer het, wat met drie eie wette vorendag gekom het om te verduidelik waarom die planete beweeg soos hulle beweeg.

Newton & rsquos Laws of Motion

As Kepler & rsquos-wette die beweging van die planete definieer, definieer Newton & rsquos-wette beweging. Met die oog op Kepler & rsquos-wette het Newton besef dat alle beweging, of dit nou die wentelbaan van die Maan om die aarde was of 'n appel wat van 'n boom afgeval het, dieselfde basiese beginsels gevolg het. & ldquoTo dieselfde natuurlike effekte, & rdquo het hy geskryf, & ldquowe moet, sover dit moontlik is, dieselfde oorsake toewys. & rdquo Vorige Aristoteliese denke, het die fisikus Stephen Hawking geskryf, verskillende oorsake aan verskillende soorte bewegings toegeken. Deur alle beweging te verenig, het Newton die wetenskaplike perspektief verskuif na 'n soeke na groot, verenigende patrone in die natuur. Newton het sy wette uiteengesit in Philosophiae Naturalis Principia Mathematica (& ldquoMathematical Principles of Natural Philosophy, & rdquo) wat in 1687 gepubliseer is.

Wet I. Elke liggaam volhard in sy toestand van rus, of van eenvormige beweging in 'n regte lyn, tensy hy gedwing word om daardie toestand te verander deur kragte wat daarop beïndruk is.

In wese sal 'n bewegende voorwerp nie die spoed of rigting verander nie, en 'n stil voorwerp sal ook nie begin beweeg nie, tensy daar 'n krag van buite is wat daarop inwerk. Die wet word gereeld in een woord saamgevat: traagheid.

Reg II. Die verandering van beweging is eweneens eweredig met die beweegkrag wat beïndruk word en word in die rigting van die regte lyn waarin die krag beïndruk word, gemaak.

Newton & rsquos se tweede wet is die herkenbaarste in sy wiskundige vorm, die ikoniese vergelyking: F = ma. Die krag van die krag (F) word gedefinieër deur hoeveel dit die beweging (versnelling, a) van 'n voorwerp met 'n mate van massa (m) verander.

Reg III. Vir elke aksie word daar altyd 'n gelyke reaksie gekant: of die onderlinge optrede van twee liggame teenoor mekaar is altyd gelyk en gerig op teenoorgestelde dele.

Soos Newton self beskryf het: & ldquoAs u 'n klip met u vinger druk, word die vinger ook deur die klip gedruk. & Rdquo

Swaartekrag

Op die bladsye van Principia het Newton ook sy wet van universele gravitasie aangebied as 'n gevallestudie van sy bewegingswette. Alle materie oefen 'n krag uit, wat hy swaartekrag noem, wat alle ander materie na sy middelpunt trek. Die krag van die krag hang af van die massa van die voorwerp: die son het meer swaartekrag as die aarde, wat op sy beurt meer swaartekrag het as 'n appel. Die krag verswak ook met afstand. Voorwerpe ver van die son af word nie beïnvloed deur die erns daarvan nie.

Newton & rsquos se wette van beweging en swaartekrag het die jaarlikse reis van die aarde & rsquos om die son verduidelik. Die aarde sou reguit vorentoe beweeg deur die heelal, maar die son oefen voortdurend ons planeet uit. Hierdie krag buig die aarde en die rsquos-pad na die son en trek die planeet in 'n elliptiese (amper sirkelvormige) baan. Sy teorieë het dit ook moontlik gemaak om die getye te verklaar en te voorspel. Die styging en daling van die oseaan se watervlakke word geskep deur die swaartekrag van die Maan as dit om die aarde wentel.

Einstein en Relatiwiteit

Die idees wat in Newton & rsquos se bewegingswette en universele gravitasie uiteengesit is, het byna 220 jaar lank onbetwis gebly totdat Albert Einstein sy teorie van spesiale relatiwiteit in 1905 aangebied het. Die Newton & rsquos-teorie hang af van die aanname dat massa, tyd en afstand konstant is ongeag waar u dit meet .

Die relatiwiteitsteorie behandel tyd, ruimte en massa as vloeibare dinge, gedefinieer deur 'n waarnemer en 'n verwysingsraamwerk. Almal van ons wat deur die heelal op aarde beweeg, is in een enkele verwysingsraamwerk, maar 'n ruimtevaarder in 'n vinnig bewegende ruimteskip sou in 'n ander verwysingsraamwerk wees.

Binne 'n enkele verwysingsraamwerk geld die wette van klassieke fisika, insluitende Newton & rsquos-wette. Maar die Newton & rsquos-wette kan die verskille in beweging, massa, afstand en tyd as gevolg van voorwerpe vanuit twee verskillende verwysingsraamwerke verklaar en verklaar. Om beweging in hierdie situasies te beskryf, moet wetenskaplikes op Einstein & rsquos relatiwiteitsteorie steun.

Teen stadige snelhede en groot skale is die verskille in tyd, lengte en massa wat deur relatiwiteit voorspel word, egter klein genoeg om konstant te lyk, en die Newton & rsquos-wette werk steeds. Oor die algemeen beweeg min dinge vinnig genoeg sodat ons relatiwiteit kan raaksien. Vir groot, stadig bewegende satelliete, definieer Newton & rsquos-wette steeds wentelbane. Ons kan dit steeds gebruik om aardwaarnemende satelliete te lanseer en hul beweging te voorspel. Ons kan dit gebruik om die Maan, Mars en ander plekke buite die aarde te bereik. Om hierdie rede sien baie wetenskaplikes Einstein & rsquos-wette van algemene en spesiale relatiwiteit nie as 'n vervanging van Newton & rsquos-bewegingswette en universele gravitasie nie, maar as die volle hoogtepunt van sy idee.


'N Heelal van tien dimensies

Superstring-teorie beweer dat die heelal tegelykertyd in tien dimensies bestaan. Krediet: Nasionale Instituut vir Tegnologie Tiruchirappalli.

As iemand 'verskillende dimensies' noem, is ons geneig om te dink aan dinge soos parallelle heelalle - alternatiewe realiteite wat parallel met ons eie bestaan, maar waar dinge anders werk of gebeur. Die realiteit van dimensies en hoe dit 'n rol speel in die ordening van ons Heelal verskil egter regtig van hierdie gewilde karakterisering.

Om dit af te breek, is dimensies bloot die verskillende fasette van wat ons as werklikheid beskou. Ons is dadelik bewus van die drie dimensies wat ons daagliks omring - dié wat die lengte, breedte en diepte van alle voorwerpe in ons heelal definieer (onderskeidelik die x-, y- en z-as).

Buiten hierdie drie sigbare dimensies, glo wetenskaplikes dat daar nog baie meer kan wees. In werklikheid stel die teoretiese raamwerk van Superstring Theory dat die heelal in tien verskillende dimensies bestaan. Hierdie verskillende aspekte is wat die heelal bestuur, die fundamentele kragte van die natuur en al die elementêre deeltjies wat daarin voorkom.

Die eerste dimensie, soos reeds opgemerk, is dit wat dit lengte gee (oftewel die x-as). 'N Goeie beskrywing van 'n eendimensionele voorwerp is 'n reguit lyn wat slegs in lengte bestaan ​​en geen ander waarneembare eienskappe het nie. Voeg daarby a tweede dimensie, die y-as (of hoogte), en u kry 'n voorwerp wat 'n tweedimensionele vorm word (soos 'n vierkant).

Die derde dimensie behels diepte (die z-as), en gee alle voorwerpe 'n gevoel van oppervlakte en 'n deursnit. Die perfekte voorbeeld hiervan is 'n kubus wat in drie dimensies bestaan ​​en 'n lengte, breedte, diepte en dus volume het. Buiten hierdie drie lê die sewe dimensies wat nie onmiddellik vir ons duidelik is nie, maar wat steeds beskou kan word as 'n direkte uitwerking op die heelal en die werklikheid soos ons dit ken.

Wetenskaplikes glo dat die vierde dimensie is tyd, wat die eienskappe van alle bekende materiaal op 'n gegewe punt beheer. Saam met die drie ander dimensies, is dit noodsaaklik om 'n voorwerp se posisie in tyd te ken, om sy posisie in die heelal te beplan. Die ander dimensies is waar dieper moontlikhede ter sprake kom, en die verduideliking van hul interaksie met die ander is waar dinge vir fisici besonder lastig raak.

Die tydlyn van die heelal, begin met die oerknal. Volgens String Theory is dit maar een van die vele moontlike wêrelde. Krediet: NASA

Volgens Superstring Theory is die vyfde en sesde dimensie waar die idee van moontlike wêrelde ontstaan. As ons kon sien na die vyfde dimensie, sou ons 'n wêreld sien wat effens anders was as ons eie, wat ons 'n manier sou gee om die ooreenkoms en verskille tussen ons wêreld en ander moontlikhede te meet.

In die sesde, sou ons 'n vlak van moontlike wêrelde sien, waar ons al die moontlike heelalle wat met dieselfde aanvanklike toestande as hierdie een (dit wil sê die oerknal), kan vergelyk en posisioneer. As u die vyfde en sesde dimensie kan bemeester, kan u in die teorie terugreis in die tyd of na verskillende toekoms gaan.

In die sewende dimensie, het u toegang tot die moontlike wêrelde wat met verskillende aanvanklike toestande begin. Terwyl die aanvanklike voorwaardes in die vyfde en sesde dieselfde was en die daaropvolgende aksies anders was, hier is alles anders as die begin van die tyd. Die agtste dimensie gee ons weer 'n vlak van sulke moontlike heelalgeskiedenisse, wat elkeen met verskillende aanvanklike toestande begin en oneindig vertak (daarom word dit oneindighede genoem).

In die negende dimensiekan ons al die moontlike heelalgeskiedenisse vergelyk, begin met al die verskillende wette van fisika en aanvanklike toestande. In die tiende en finale dimensie, kom ons by die punt waarin alles moontlik en denkbaar gedek word. Hierbenewens kan ons deur geringe sterflinge niks voorstel nie, wat dit die natuurlike beperking maak van wat ons in terme van dimensies kan bedink.

Die bestaan ​​van hierdie bykomende ses dimensies wat ons nie kan aanskou nie, is nodig vir die String Theory om konsekwentheid in die natuur te hê. Die feit dat ons slegs vier dimensies van die ruimte kan waarneem, kan verklaar word deur een van twee meganismes: óf die ekstra afmetings word op 'n baie klein skaal gekompakteer, of anders kan ons wêreld leef in 'n driedimensionele submanifold wat ooreenstem met 'n bran, op wat alle bekende deeltjies, behalwe swaartekrag, beperk sou word (ook bekend as brane theory).

Die bestaan ​​van ekstra dimensies word verklaar aan die hand van die Calabi-Yau-verdeelstuk, waarin al die intrinsieke eienskappe van elementêre deeltjies versteek is. Krediet: 'n Hanson

As die ekstra afmetings gekompakteer word, moet die ekstra ses afmetings in die vorm van 'n Calabi-Yau-spruitstuk wees (hierbo getoon). Alhoewel dit ons sintuie onmerkbaar is, sou dit die vorming van die heelal van die begin af regeer het. Daarom glo wetenskaplikes dat hulle deur die tyd terugkyk deur teleskope te gebruik om lig uit die vroeë heelal (dit wil sê miljarde jare gelede) raak te sien, moontlik sou kon sien hoe die bestaan ​​van hierdie addisionele dimensies die evolusie van die kosmos kon beïnvloed.

Net soos ander kandidate vir 'n grootse verenigende teorie - oftewel Theory of Everything (TOE) - is die oortuiging dat die heelal bestaan ​​uit tien dimensies (of meer, afhangende van die model van die stringteorie wat u gebruik), 'n poging om die standaardmodel van deeltjiefisika met die bestaan ​​van swaartekrag. Kortom, dit is 'n poging om te verduidelik hoe alle bekende kragte in ons heelal op mekaar inwerk, en hoe ander moontlike heelalle self kan werk.

Vir bykomende inligting, hier is 'n artikel oor Universe Today oor parallelle heelalle, en 'n ander oor 'n parallelle heelal wat wetenskaplikes gedink het hulle vind dat dit nie eintlik bestaan ​​nie.

Daar is ook 'n paar ander wonderlike bronne aanlyn. Daar is 'n wonderlike video wat die tien dimensies breedvoerig verduidelik. U kan ook na die PBS-webwerf kyk vir die TV-show Elegant universe. Dit het 'n wonderlike bladsy oor die tien dimensies.

U kan ook na Astronomy Cast luister. U sal dalk episode 137 Die grootskaalse struktuur van die heelal interessant vind.


Nuwe studie toon hoe tieners geleer kan word om meer rasioneel op te tree

Die probleme met tieners is by baie ouers bekend: hulle is hormoongedrewe, opwindende bundels eros met 'n skokkende onvermoë om die gevolge van hul optrede deur te dink. Adolessente sloer nie net nie en bestee te veel tyd aan videospeletjies. Hulle stel hulself in gevaar deur te vinnig en te roekeloos te ry, soms onder die invloed van alkohol. Hulle neem dwelms wat hul gesondheid en welstand bedreig. En hulle neem onbeskermde seks teen 'n onrusbarende (indien nou ietwat laer) tempo, wat tienerswangerskappe en seksueel oordraagbare infeksies (SOI's) tot gevolg het. David Dobbs het 'n paar jaar gelede die wetenskap van die neem van risiko's vir tieners saamgevat National Geographic:

Ons loop die risiko groter as tieners as ooit tevore. Dit blyk betroubaar in die laboratorium, waar tieners meer kanse waag in beheerde eksperimente wat alles van kaartspeletjies tot gesimuleerde bestuur insluit. En dit wys in die werklike lewe, waar die tydperk van ongeveer 15 tot 25 pieke in allerhande riskante ondernemings en lelike resultate meebring. Hierdie ouderdomsgroep sterf aan ongelukke van byna elke soort (behalwe werkongelukke) teen hoë pryse. Die meeste dwelm- of alkoholmisbruik op lang termyn begin gedurende tienerjare, en selfs mense wat later verantwoordelik drink, drink dikwels te veel as tieners. Veral in kulture waar tienerbestuur algemeen is, eis dit baie swaar: in die VSA is een uit elke drie sterftes teen tieners weens motorongelukke, waarvan baie alkohol betref.

Dit is die rede waarom die motorhuuragentskap so huiwerig is om aan bestuurders onder die ouderdom van 25 te huur en 'n skerp premie te eis. Daarom is die versekeringstariewe hoër vir jonger bestuurders, veral jong mans. 'N Mens kan aflei dat die brein van tieners swak bedraad is, wat daartoe lei dat hulle op instink reageer sonder om die risiko's van hul gedrag te waardeer. Hierdie aanname word so wyd aangeneem as wat dit diep en nuuskierig verkeerd is.

Dit is nie so dat tieners nie die vermoë het om rasionaliteit te hê of hulself as immuun teen sterftes beskou nie. Laurence Steinberg, 'n ontwikkelingsielkundige wat deur Dobbs aangehaal word, sê tieners is net so in staat om oordeelkundig oor voordele en risiko's te dink as volwassenes as wat hulle die risiko eintlik oorskat, sê hy. Tieners doen verstaan ​​die risiko's wat hulle neem. Hulle het net ignoreer hierdie risiko's te dikwels, soms met tragiese resultate.

Sielkundiges Valerie Reyna van Cornell en Britain Mills van die Universiteit van Texas voer aan dat die sielkundiges Valerie Reyna van Cornell en Britain Mills van die Universiteit van Texas in 'n nuwe studie die ondersoek na alternatiewe intervensies om veiliger gedrag aan te spoor, aansienlik meer effektief is as om net te gee aan studente. hulle die instrumente om risiko's te weeg deur hul eie rasionaliteit te gebruik. Reyna en Mills se eksperiment het 734 tieners van Arizona, Texas en New York blootgestel aan een van drie verskillende leerplanne om vas te stel wie die suksesvolste is om veiliger seks te bevorder. Een derde van die 14-19-jariges is toegewys aan 'n program vir seksuele opvoeding, bekend as die vermindering van die risiko (RTR), een derde aan 'n verbeterde model, RTR +, en die laaste derde aan 'n beheerde kurrikulum sonder inhoud vir seksuele opvoeding.

Beide die RTR- en RTR + -klasse het die risiko's van seksuele gedrag beklemtoon, en veral die risiko's van swangerskap en infeksie weens onbeskermde seks. Hier is byvoorbeeld hoe die opvoeders die idee teruggedryf het dat seks uiteindelik tot swangerskap sal lei:

Gegewe die waarskynlikheid om swanger te raak vir een daad van onbeskermde seks, en as hulle so een keer per maand aanvaar, het die deelnemers aan die klas kaartjies uit 'n hoed getrek wat aandui of hulle swanger geword het. Deelnemers wat 'swanger raak', staan ​​en die aktiwiteit duur een jaar (12 trekkings) voort, waarop die hele klas gewoonlik staan. Met ander woorde, die aktiwiteit was so gestruktureer dat feitlik al die deelnemers aan die einde van die gesimuleerde jaar swanger geword het (of iemand swanger geraak het). Die aktiwiteit het gepaard gegaan met 'n interaktiewe klasbespreking oor presies wanneer hulle swanger geword het tydens die oefening, wanneer hulle die baba sou kry en wat die swangerskap vir die deelnemer sou beteken. Deelnemers bespreek byvoorbeeld hoe swangerskap en baba hul eie planne vir die toekoms sou beïnvloed (soos om universiteit toe te gaan) en hoe dit hul lewe op kort termyn sou beïnvloed (soos betrokkenheid by buitemuurse aktiwiteite). Vergelykbare besprekings en aktiwiteite is aangebied vir SOI-infeksies.

Dit is redelik kragtige dinge, en dit het 'n impak gehad op die tieners se sekspraktyke gedurende die daaropvolgende maande in vergelyking met diegene wat glad nie seksopvoeding ontvang het nie. Maar hierdie benadering was nie so effektief soos in RTR + -klaskamers nie, waar die oefening aan die einde saamgevat is met 'n "kern" -verklaring, wat die outeurs ook 'die pragmatiese kern' noem:

"Selfs lae risiko's is 100% as u dit aanhou doen."

'Swangerskap kan die eerste maand, op 6 maande of 13 maande plaasvind', skryf Reyna en Mills, 'maar die kern is dat dit oor 'n jaar' sou gebeur '.' So 'n "kategoriese kontras tussen 'n gebeurtenis wat plaasvind en nie plaasvind nie (alles-of-niks), tesame met herhaalde aandag aan die waardes van die adolessente, het gelei tot indrukwekkende resultate as gevolg van bloot die resitasie of demonstrasie van die risiko. Die slotsom van die outeurs - ja, die kern van hul artikel - word in hierdie grafiek gevind. Volg die soliede swart lyn:

Deur tieners bloot deur die risiko's van onbeskermde seks te lei (die streeplyn), kan dit die mate waartoe hulle risiko's met seksmaats neem, verlaag - dit verbeter wel hul "Hazard" -profiel oor 'n leerplan sonder seksuele opvoeding (die stippellyn). Maar om die moraal van die verhaal in hul koppe te boor na om dit deur die risiko's te loop (die soliede swart streep) is nog meer effektief. Wat geld vir seksredaksie, moet geld vir drink, bestuur, dwelms en meer: ​​adolessente moet die slotsom hoor en dit hard en duidelik hoor. Om suggestief te wees is nie genoeg nie.


Die gevaar van hiper-spesialisasie

Die eksplosiewe uitbreiding van kennis wat in die middel van die 1800's begin het, het gelei tot hiper-spesialisasie binne en buite die akademie. Selfs binne 'n enkele vakgebied, byvoorbeeld filosofie of fisika, verstaan ​​professionele mense mekaar dikwels nie. Soos ek vroeër hier geskryf het: 'Hierdie versplintering van kennis binne en buite die akademie is die kenmerk van ons tyd, 'n versterking van die botsing van die twee kulture wat die fisikus en romanskrywer C.P. Snow sy kollegas in Cambridge in 1959 vermaan het.' Die verlies is tasbaar, intellektueel en sosiaal. Kennis is nie vaardig vir reduksionisme nie. Sure, a specialist will make progress in her chosen field, but the tunnel vision of hyper-specialization creates a loss of context: you do the work not knowing how it fits into the bigger picture or, more alarmingly, how it may impact society.

Many of the existential risks we face today — AI and its impact on the workforce, the dangerous loss of privacy due to data mining and sharing, the threat of cyberwarfare, the threat of biowarfare, the threat of global warming, the threat of nuclear terrorism, the threat to our humanity by the development of genetic engineering — are consequences of the growing ease of access to cutting-edge technologies and the irreversible dependence we all have on our gadgets. Technological innovation is seductive: we want to have the latest "smart" phone, 5k TV, and VR goggles because they are objects of desire and social placement.


10 Most Famous Scientific Theories That Were Later Debunked

The most genuine merit of science is probably its readiness to admit its mistakes (usually!). The theories in science are always being reconsidered and scrutinized. Modern research often rejects old ideas, hoaxes and myths.

Today’s post on our Science Blog will discuss ten of the most popular and influential scientific discoveries that were based on dubious data, and were consequently proven wrong, debunked and replaced with more reliable and logical modern theories.

1- Fleischmann–Pons’s Nuclear Fusion

Cold fusion is a supposed kind of nuclear reaction that would occur at relatively low temperatures compared with hot fusion. As a new type of nuclear reaction, it gained much popularity after reports in 1989 by famous electrochemists Stanley Pons and Martin Fleischmann. The craze about cold fusion became weaker as other scientists, after trying to repeat the experiment, failed to get similar results.

1a – One of Modern Science’s Greatest Misconceptions

The misconception that mass is destroyed in nuclear reactions.

2- Phrenology

Now widely considered as a pseudoscience, phrenology was the study of the shape of skull as indicative of the strengths of different faculties. Modern scientific research wiped it out by proving that personality traits could not be traced to specific portions of the brain.

3- The Blank Slate

The Blank Slate theory (or Tabula rasa), widely popularized by John Locke in 1689, proposed that individuals are born without built-in mental content and that their knowledge comes from experience and perception. Modern research suggests that genes and other family traits inherited from birth, along with innate instincts of course, also play a very important role.

4- Luminiferous Aether

The aether (or ether) was a mysterious substance that was thought to transmit light through the universe. The idea of a luminiferous aether was debunked as experiments in the diffraction and refraction of light, and later Einstein’s special theory of relativity, came along and entirely revolutionized physics.

5- Einstein’s Static (or Stationary) Universe

A static universe, also called a “stationary” or “Einstein” universe, was a model proposed by Albert Einstein in 1917. It was problematic from the beginning. Edwin Hubble’s discovery of the relationship between red shift obliterated it by completely demonstrating that the universe is constantly expanding.

6- Martian Canals

The Martian canals were a network of gullies and ravines that some 19th century scientists erroneously thought to exist on Mars. First detected in 1877 by Italian astronomer Giovanni Schiaparelli, modern telescopes and imaging technology completely debunked the myth. The “canals” were actually found to be a mere optical illusion.

7- Phlogiston Theory

First postulated in 1667 by German physician Johann Joachim Becher, Phlogiston Theory is an obsolete scientific theory regarding the existence of “phlogiston”, a fire-like element, which was contained within combustible bodies and released during combustion. The theory tried to explain burning processes such as combustion and the rusting of metals, which are now jointly termed as “oxidation”.

8- The Expanding or Growing Earth

The Expanding Earth or Growing Earth is a hypothesis suggesting that the position and relative movement of continents is dependent on the volume of the Earth increasing. Modern science has turned down any expansion or contraction of the Earth.

9- Discovery of the Planet Vulcan

A small planet that was supposed to exist in an orbit between Mercury and the Sun, French mathematician Urbain Jean Joseph Le Verrier coined the name “Vulcan” while trying to explain the nature of Mercury’s orbit. No such planet was ever discovered, while the orbit of Mercury was explained in detail by Albert Einstein’s theory of general relativity.

10- Spontaneous (or Equivocal) Generation

Spontaneous generation or equivocal generation is an obsolete principle concerning the origin of life from inanimate matter. The hypothesis was brought out by Aristotle who advocated the work of earlier natural philosophers. It was proven wrong in the 19th century by the experiments of Louis Pasteur, drawing influence from Francesco Redi who was an early proponent of germ theory and cell theory.

More from FamousScientists.org:

Kommentaar

RITAHEAD, the bible is a BOOK. I could write a book that says the Earth is flat and the Moon is made of green cheese and would that make it true? Of course not! The Bible is wrong about many things. Including the value of the pi constant. Deal with it.

Scientists use Hubble Telescope to comment the entire universe would be expanding.

How could Hubble Telescope work in reality? It simply works by collecting light from the sky through the use of primary mirror in this Telescope and then to reflect it upon a secondary mirror for analysis. However, the reflection of light by means of primary mirrors could result in obscure image in secondary mirror. The reason is simply lights could reflect in any directions and angles from any parts of primary mirror. As a result, overlapping of lights on secondary mirrors as a result of reflection from primary mirrors could be possible to the ultimate formation of obscure images. These collective obscure images could lead to false information that the entire universe could be expanding.

Hubble Space Telescope uses the same technique as Hubble Telescope to collect lights from the sky for analysis. Thus, false images could be gathered too.

Thus, fake images from the collection of lights from the sky through the reflective mirrors would cause information that would be gathered from Hubble Space or Hubble Telescope might not to be reliable.

I hope we can soon add the cholesterol theory of heart disease. It’s been debunked, but getting it to die is proving difficult.

I wished they would have mentioned the carbon dating and radioactive dating. One thing I did learn in science is that to prove your theory, you have to have a control. How can they prove that bones are millions of years old? My bible tells me the earth is not that old.

In genetics the definition of the “GENE” has changed over and over since it was coined by Johansson in 1909.

Gene as unit of function
Gene as unit of recombination
Gene as unit of mutation
One gene one enzyme concept
The central Dogma DNA->RNA->protein

All these views have been revised by newer concepts.
An overview of all outmoded definitions and the problematic attempts to offer a current defention that is valid now, was published in
http://genome.cshlp.org/content/17/6/669

neo-darwinism is largely debunked as explanation for increasing biological complexity. This theory, largely composed of population genetic concepts to understand how selection could bring change is still valid to explain variability within species.

The major explanation for increase of organismal complexity, i.e. from prokaryotes to eukaryotes, from single cell to multicellular organisms, from primitive to complex species is not explained by neodarwinism.

Horizontal gene transfer, Genome duplication (polyploidization and subsequent genome fragmentation) are largely singular events caused by drift rather than mutation and selection.

It is hardly understood by lay people how the current genomic revolution is reshaping evolutionary concepts.

And I have not even mentioned the revival of Lamarckism.

I think this contemporary example is a much nicer example that outmoded phlogiston theories from times before modern sciences had its current rigour

Some of these are dubious at best. For example, the luminiferous aether wasn’t debunked it was not needed in the new theories, and so it dropped out of physics, but that’s a very different matter. Locke’s objection to innate ideas, principles, knowledge, etc., not only wasn’t a scientific theory, but isn’t touched by genetic theory, or by any scientific theory. Moreover, he was happy to accept that we have innate capacities and abilities, which is all that science has attempted to explain in terms of genetics, etc. No-one, to the best of my knowledge, claimed to have discovered Vulcan, nor was its existence a theory, it was part of a hypothesis designed 9as you point out) to explain the ways in which Mercury’s orbit failed to accord with Newtonian physics.

A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of knowledge that has been repeatedly confirmed through observation and experiment.[1][2] Scientists create scientific theories from hypotheses that have been corroborated through the scientific method, then gather evidence to test their accuracy. As with all forms of scientific knowledge, scientific theories are inductive in nature and do not make apodictic propositions instead, they aim for predictive and explanatory force.[3][4]

1 National Academy of Sciences, 1999
2 AAAS Evolution Resources
3 Schafersman, Steven D. “An Introduction to Science”.
4 American Association for the Advancement of Science, Project 2061

Interesting piece. The only I have to point out it that the majorities of these were never widely held theories. Instead most of them were either hypothesis or were only believed to be true by a small percent of the scientific community. There is a big difference between hypothesis and scientific theory.

This is very wonderful. Science in its nature of existence is a circulating event in which its theories can be formulated and debunked. Thanks for the hard job done.


The Expanding Universe

Every model of the universe must include the expansion we observe. Another key element of the models is that the cosmological principle (which we discussed in The Evolution and Distribution of Galaxies) is valid: on the large scale, the universe at any given time is the same everywhere (homogeneous and isotropic). As a result, the expansion rate must be the same everywhere during any epoch of cosmic time. If so, we don’t need to think about the entire universe when we think about the expansion, we can just look at any sufficiently large portion of it. (Some models for dark energy would allow the expansion rate to be different in different directions, and scientists are designing experiments to test this idea. However, until such evidence is found, we will assume that the cosmological principle applies throughout the universe.)

In Galaxies, we hinted that when we think of the expansion of the universe, it is more correct to think of space itself stretching rather than of galaxies moving through static space. Nevertheless, we have since been discussing the redshifts of galaxies as if they resulted from the motion of the galaxies themselves.

Now, however, it is time to finally put such simplistic notions behind us and take a more sophisticated look at the cosmic expansion. Recall from our discussion of Einstein’s theory of general relativity (in the chapter on Black Holes and Curved Spacetime) that space—or, more precisely, spacetime—is not a mere backdrop to the action of the universe, as Newton thought. Rather, it is an active participant—affected by and in turn affecting the matter and energy in the universe.

Since the expansion of the universe is the stretching of all spacetime, all points in the universe are stretching together. Thus, the expansion began everywhere at once. Unfortunately for tourist agencies of the future, there is no location you can visit where the stretching of space began or where we can say that the Big Bang happened.

To describe just how space stretches, we say the cosmic expansion causes the universe to undergo a uniform change in scale over time. By scale we mean, for example, the distance between two clusters of galaxies. It is customary to represent the scale by the factor R if R doubles, then the distance between the clusters has doubled. Since the universe is expanding at the same rate everywhere, the change in R tells us how much it has expanded (or contracted) at any given time. For a static universe, R would be constant as time passes. In an expanding universe, R increases with time.

Figure 1. Expansion and Redshift: As an elastic surface expands, a wave on its surface stretches. For light waves, the increase in wavelength would be seen as a redshift.

If it is space that is stretching rather than galaxies moving through space, then why do the galaxies show redshifts in their spectra? When you were young and naïve—a few chapters ago—it was fine to discuss the redshifts of distant galaxies as if they resulted from their motion away from us. But now that you are an older and wiser student of cosmology, this view will simply not do.

A more accurate view of the redshifts of galaxies is that the light waves are stretched by the stretching of the space they travel through. Think about the light from a remote galaxy. As it moves away from its source, the light has to travel through space. If space is stretching during all the time the light is traveling, the light waves will be stretched as well. A redshift is a stretching of waves—the wavelength of each wave increases (Figure 1). Light from more distant galaxies travels for more time than light from closer ones. This means that the light has stretched more than light from closer ones and thus shows a greater redshift.

Thus, what the measured redshift of light from an object is telling us is how much the universe has expanded since the light left the object. If the universe has expanded by a factor of 2, then the wavelength of the light (and all electromagnetic waves from the same source) will have doubled.


The expanding universe

In 1929, an American astronomer working at the Mt. Wilson Observatory in southern California made an important contribution to the discussion of the nature of the universe. Edwin Hubble had been at Mt. Wilson for 10 years, measuring the distances to galaxies, among other things. In the 1920s, he was working with Milton Humason, a high school dropout and assistant at the observatory. Hubble and Humason plotted the distances they had calculated for 46 different galaxies against Slipher's recession velocity and found a linear relationship (see Figure 6) (Hubble, 1929).

Figure 6: The original Hubble diagram. The relative velocity of galaxies (in km/sec) is plotted against distance to that galaxy (in parsecs a parsec is 3.26 light years). The slope of the line drawn through the points gives the rate of expansion of the universe (the Hubble Constant). (Originally Figure 1, from "A Relation Between Distance and Radial Velocity Among Extra-Galactic Nebulae," Proceedings of the National Academy of Sciences, Volume 15, Issue 3, 1929: p. 172. © Huntington Library, San Marino, CA.) image © The Huntington Library

In other words, their graph showed that more distant galaxies were receding faster than closer ones, confirming the idea that the universe was indeed expanding. This relationship, now referred to as Hubble's Law, allowed them to calculate the rate of expansion as a function of distance from the slope of the line in the graph. This rate term is now referred to as the Hubble constant. Hubble's initial value for the expansion rate was 500 km/sec/Megaparsec, or about 160 km/sec per million-light-years.

Knowing the rate at which the universe is expanding, one can calculate the age of the universe by in essence "tracing back" the most distant objects in the universe to their point of origin. Using his initial value for the expansion rate and the measured distance of the galaxies, Hubble and Humason calculated the age of the universe to be approximately 2 billion years. Unfortunately, the calculation was inconsistent with lines of evidence from other investigations. By the time Hubble made his discovery, geologists had used radioactive dating techniques to calculate the age of Earth at about 3 billion years (Rutherford, 1929) – or older than the universe itself! Hubble had followed the process of science, so what was the problem?

Even laws and constants are subject to revision in science. It soon became clear that there was a problem in the way that Hubble had calculated his constant. In the 1940s, a German astronomer named Walter Baade took advantage of the blackouts that were ordered in response to potential attacks during World War II and used the Mt. Wilson Observatory in Arizona to look at several objects that Hubble had interpreted as single stars. With darker surrounding skies, Baade realized that these objects were, in fact, groups of stars, and each was fainter, and thus more distant, than Hubble had calculated. Baade doubled the distance to these objects, and in turn halved the Hubble constant and doubled the age of the universe. In 1953, the American astronomer Allan Sandage, who had studied under Baade, looked in more detail at the brightness of stars and how that varied with distance. Sandage further revised the constant, and his estimate of 75 km/sec/Megaparsec is close to our modern day estimate of the Hubble constant of 72 km/sec/Megaparsec, which places the age of the universe at 12 to 14 billion years old.

The new estimates developed by Baade and Sandage did not negate what Hubble had done (it is still called the Hubble constant, after all), but they revised it based on new knowledge. The lasting knowledge of science is rarely the work of an individual, as building on the work of others is a critical component of the process of science. Hubble's findings would have been limited to some interesting data on the distance to various stars had it not also built on, and incorporated, the work of Slipher. Similarly, Baade and Sandage's contribution were no less significant because they "simply" refined Hubble's earlier work.

Since the 1950s, other means of calculating the age of the universe have been developed. For example, there are now methods for dating the age of the stars, and the oldest stars date to approximately 13.2 billion years ago (Frebel et al., 2007). The Wilkinson Microwave Anisotropy Probe is collecting data on cosmic microwave background radiation (Figure 7). Using these data in conjunction with Einstein's theory of general relativity, scientists have calculated the age of the universe at 13.7 ± 0.2 billion years old (Spergel et al., 2003). The convergence of multiple lines of evidence on a single explanation is what creates the solid foundation of scientific knowledge.

Figure 7: Visual representation of the cosmic microwave background radiation, and the temperature differences indicated by that radiation, as collected by the Wilkinson Microwave Anisotropy Probe. image © NASA/WMAP Science Team

Major ideas in science are rarely the work of


Question Edgeless universe?

You will probably get a lot of variety in replies.
I don't think you will meet yourself coming back.

I will kick off with one idea I had long ago. If you got to the edge of the Universe (whatever that may mean) there is nothing beyond. If you set off away from the Universe you would become the edge of the Universe. In other words you need a frame of reference. The 'edge' of the Universe must be defined by something. A star ? ? ? whatever. When you set off beyond, you become the new defining point.

You will get more sophisticated replies (maybe including one from me) but I thought I would kick off with a simple one.

Enjoy your visits here. Look through the topics.

David-J-Franks

David-J-Franks

FYI folks. How Big Is the Universe? The answer provided in this report "We can only see a tiny, little bubble of [the universe]. And what's outside of that? We don't really know," Kinney said. But by calculating the size of that little bubble, scientists can estimate what's outside of it. Scientists know that the universe is 13.8 billion years old, give or take a few hundred million years. That means that an object whose light has taken 13.8 billion years to reach us should be the very farthest object we can see. You might be tempted to think that gives us an easy answer for the size of the universe: 13.8 billion light-years. But keep in mind that the universe is also continuously expanding at an increasing rate. In the amount of time that light has taken to reach us, the edge of the bubble has moved. Luckily, scientists know just how far it's moved: 46.5 billion light-years away, based on calculations of universe’s expansion since the big bang."

My observation. The 46.5 billion LY distance comes from the comoving radial distance since the BB using z=1000 or more for the redshift of the CMBR. COSMOLOGY CALCULATORS However, David, Cat, et al. My telescopes cannot see anything that far away ---Rod

David-J-Franks

First of all, I would like to suggest that the dictionary definition of the universe, ie "it is everything there is", is out of date, I suggest it was thought of well before the big bang model. This definition doesn't allow for multiple or infinite other universes or multiverse theories etc. So, I would like to add to this thread with some of my own personal ideas.

Our universe started with a finite size, it has a finite rate of expansion and a finite age, so it must now have a finite size. I now treat the universe as an object. Objects exist in a space, they don't create all of space. I think the space our universe is in must be infinite, I call this space 'The Infinite'. So, I now see 'The Infinite' as 'everything there is'.

I also believe nature does not allow one-off processes, if it's possible once then it's always possible. The big bang was a natural process, so, given an infinite space as in 'The Infinite', there must be an infinite number of universes.

So, my answer to your question is that the universe is expanding into the space of 'The Infinite'. Space is a tangible 'something' such as quantum field/foam/fluctuations, vacuum energy, dark energy etc, it's not a void. So as well as expanding into space, space also came out of the big bang along with its matter and energy

Catastrophe

Approaching asteroid? Is this THE one?

I shouted "Thank rod for that".
My wife thought I shouted "Thank god for that"
I said "Not much difference",

He frightens away the nasties.

Catastrophe

Approaching asteroid? Is this THE one?

"If it has a finite size there must be a beyond"

A perfect example of anthropomorphic delusion.

You can take a horse to water but you cannot make it drink.
(Old proverb).

David-J-Franks

I shouted "Thank rod for that".
My wife thought I shouted "Thank god for that"
I said "Not much difference",

He frightens away the nasties.

Last night you appear to have called me ignorant and stupid. You or a moderator has since removed it. Here is a copy of the wording from that post for all to see. It's obvious that post was directed at me because I was the only one posting at that time and it came very soon after my posts.

"There is a word for playing around with something to please one's own ignorance..

I seem to have forgotten what it is."

Also, looks like you are calling me nasty, again obviously directed at me for the same reasons as above.

If you don't agree with my ideas please say why, or direct me to better information, or suggest your own ideas, even make fun of it, as you have done with Kabones question, but please don't call me stupid, ignorant and nasty.

It would also help others by saying why you think my ideas are wrong, rather than calling me stupid in the form of a riddle.

I stayed up extra late to write my posts, so I saw your posts last thing, and so went to bed hurt and disappointed.

I got up this morning with my mind churning around thinking how to reply, only to find the post removed. Whoever removed it, shows it was out of order.

David-J-Franks

"If it has a finite size there must be a beyond"

A perfect example of anthropomorphic delusion.

You can take a horse to water but you cannot make it drink.
(Old proverb).

To add insult to injury, you're now suggesting I'm deluded. Again, it would help everyone if you say why my ideas are a delusion, rather than calling me deluded.

In my opinion, it is a perfect example of arrogance to ridicule peoples ideas (again with riddles) without giving a reason.

Wolfshadw

The post was removed by the person who wrote the post.

I will caution all parties to remain respectful in your responses.

David-J-Franks

"The point is that the Universe is complete. By definition there is nothing beyond."

Now take that on board please

One of the most mainstream ideas at the moment is the 'Eternal Inflation' model of the big bang. This has it that bubble universes are continuously popping into existence out of an eternal inflation field. OUR universe is one such bubble of an infinite number of other bubble universes.

There are many other theories which postulate multiple or infinite other universes.

According to this theory and others, and to continue in the tone of your post

OUR universe is NOT complete it is NOT 'everything there is', so accordingly there IS a beyond.

The word now to describe 'everything there is' becomes 'The Multiverse' not 'The Universe'

Now take that on board, please

David-J-Franks

The post was removed by the person who wrote the post.

I will caution all parties to remain respectful in your responses.

Thank you for that information, I wrote my reply to Catastrophe in the most respectful way my English would allow, for example using words such as 'appears to' and 'looks like', just in case I had misinterpreted his riddles. But I hope everyone can understand that I had to reply. For that reason thankyou for not deleting my post.

I've had great respect for Catastrophe, we've had many great conversions.

My latest reply to Catastrophe was a little acidic as I hit the reply button before I saw your post.

Anyway, back to normal now.

David-J-Franks

Without researching I' under the impression that the maths has several possibilities space can be flat, or with positive or negative curvature or with enough curvature to form a closed space, which I guess you are alluding to. If you believe in this closed space, then yes you will always come back to your starting point, or see the same galaxy whichever way you go round.

To the best of my knowledge, I think the best measurements so far of the universe point to it being flat with a good degree of accuracy. The error in these readings also suggest minimum size of the Whole Universe to be 250 times the size of the Observable Universe. For if it were smaller than this then our instruments would be sensitive enough to detect an unevenness with space.

David-J-Franks

QUOTE
If I start out in the opposite direction eventually I will also get to the galaxy.
QUOTE

To put it politely. this is "blowing in the wind".

The Universe is a large place. You don't have a compass. You don't have a spacesuit. You don't have FLT. You are not immortal.

Your premise is leaking badly.

David-J-Franks

Great, yes the universe is a sphere, but we live inside it, a 3D space. We are not flatlanders walking around the surface of it. Therefore, isn't there an inside and outside to it?

I'm guessing here that Kabone means the edge of the universe is the surface of this sphere?

David-J-Franks

Good. I can be my nice friendly self

Sorry, but I still have the same problem. An edgeless Universe is directly analogous to the seamless surface on a sphere. As you say, if you accept this analogy, you start at a point, say Quito which is virtually on the Equator. Set off in a straight line, which is actually the curved Equator, and you get back to Quito. A "straight" line from Quito can now be to the Moon, but this would be an extra dimension for the flatlander confined to the surface of the sphere. Do not be confused by my analogy of the Earth. I assume we can agree all that?
Now if the Universe is the sphere in the analogy, as the Universe expands the surface of the sphere expands. We, as flatlanders, cannot get off the surface of the sphere = Universe. The distance between us increases but we are still on the "surface".
The problem is we are trying to relate mere humans to the whole Universe, about which we know next to nothing. What the Universe is expanding into, is a non-question. The big problem I have with the Expanding Universe" is that we (objects) are not expanding with it. If ALL were expanding we would not know it, since our rulers would be expanding too. That, I believe, is a flaw in the Expansion theory. By analogy, the surface of the sphere = galaxy and the "into" bit relates to the expansion of the surface. No, you will say, it is expanding "outwards". You are correct, but that is a different dimension unknown to the flatlander. That dimension is unknown to us and it is nie the "into" in your question: "Into what is the Universe expanding. Your answer is: "The Universe, as a surface, is expanding. Expansion perpendicular to that surface is in a dimension we cannot detect. It is not in a space dimension familiar to us. Any attempt o make it so is anthropomorphic.

I hope that helps. I am very happy to continue the discussion

This seems like a good description of closed space such as Kabone is enquiring about, except instead of Quito he's using galaxies. So I'm puzzled why there's a misunderstanding between you both?

Where not flatlanders, so wouldn't a more useful analogy be that we live inside the 3D space of your sphere? then we can move around inside and outside of the sphere, and the surface of the sphere becomes the edge of the universe. So as the universe expands the sphere gets bigger and things inside still move apart. Whatsmore it now gives meaning to what the universe is expanding into. Any good?

David-J-Franks

David-J-Franks, Catastrophe, et al. I see references to eternal inflation and the multiverse. Here is a 14-May report some may find interesting. The Founder of Cosmic Inflation Theory on Cosmology's Next Big Ideas, "Physicist Alan Guth, the father of cosmic inflation theory, describes emerging ideas about where our universe comes from, what else is out there, and what caused it to exist in the first place."

The brief report has some interesting graphs. This *origin model* uses repulsive gravity force *in the beginning* and space expanding > 1E+20 c. There are those in science who live for theory, I enjoy the practical side of the scientific method. What we can observe and verify like Galileo could show others the tiny lights moving around Jupiter when debating the geocentric astronomy teachers. Quantum mechanics has verifiable observations based upon experiments conducted in laboratories, so does the heliocentric solar system astronomy. I do not consider that inflation, multiverse, and eternal inflation theories or string theory is on the same scientific level of verification (95+% confidence level for example) as particle experiments in QM or heliocentric solar system astronomy or for example, exoplanet studies.---Rod

David-J-Franks

"If it has a finite size there must be a beyond"

A perfect example of anthropomorphic delusion.

You can take a horse to water but you cannot make it drink.
(Old proverb).

Catastrophe

Approaching asteroid? Is this THE one?

You should know that I am a peaceable person. I am very sorry that things went awry round about posts 30-35 and I will say publicly that I regret anything that made you upset.
If this: "Have we found the edge of the Universe? All About Space May 2020 pp 40-46 had appeared sooner, I would have pointed you to it and probably retired from the thread.
Sadly, we both got involved in IMHO silly squabbles about the meaning of inside and outside and up down and around (figuratively speaking) and completely "lost the plot".
Not wishing to spoil the tone of this post, I would ask you politely to please re-read the Quito analogy section.
I, for one, would be very happy if we can continue this thread in a positive manner, without words of war and exaggerated misunderstandings,
Wishing you health and happiness in these difficult times

Catastrophe

Approaching asteroid? Is this THE one?

"So why don't you think there is a boundary (edge) and a beyond for the universe?"

I will now do my best to answer your question in a polite and constructive manner. By that, I am conveying that it will be polite, and I will try to answer it in an understandable way.

As you will see, there are many views in the article quoted. All about Space, Issue 104. There are unknowable things in the Universe and this may be one of them. My personal view is that there are problems of semantics. Our vocabularies (I include all humanity's) are incapable of describing certain issues. This may be one of them and, I believe this was the root of our communication difficulties. I would point you here to the science of General Semantics as introduced in Science and Sanity by Alfred Korzybski.

You mention straight lines and meeting yourself etcetera. I will not go back to my view that if you propose impossible starting conditions, such as being at the edge of the Universe (Who knows where that is, etc,) you will not get productive answers,. Take that off the table.

Let us assume you are at Quito. Your 'straight line' is around the Equator, governed by gravity. If you take the flatlander analogy, this means that you do return to your starting position - Quito. If you apply that to the Universe (or our universe, if you prefer - that is irrelevant in this example), and if the Universe is circular then you will return to the same place Not mentioning that there is no way whatsoever to know where that place is / was. Meeting yourself in Quito is not actually possible, but you could have left a marker saying "I was here". So your argument stands, there. Going around 'our universe' there is no way to identify that location.

Let me go back to the Quito analogy. If we were flatlanders, and all this stuff is widely discussed and available, we would behave and return exactly as you described.

Now, to the flatlander, there is no 3rd space dimension. He (or she, hereinafter assumed) has no appreciation of what we call our 3rd space dimension. Daar is no edge to his universe.

Whilst not engaging in the flatlander assumption, I quote from the article referenced above:

QUOTE
There is no current reason to suspect that the Universe ends with our cosmic horizon, just as we know that the Earth doesn’t end just because the rest of the planet is hidden from view by its curvature.
QUOTE

If we return to our flatlander analogy, we can say that the flatlander will know of the existence of the surface of the sphere, which will be the whole discoverable universe to him (granted it continues in a 3rd time dimension).

We know that the flatlander has no spatial sense to discover a non-existant (to him) 3rd space dimension. He may face the same dilemma that we face, namely that if his universe is expanding (as ours may be) then distances on the surface will increase, measured by his local measuring sticks.

INTERPOLATION begins
We do not know why this happens. If everything were to expand, including our rulers, then our measurements of the Universe would show no expansion. If we measure a table in our living room and it measures 4 feet and it expands x 2, our rulers tell us 8 feet. If the ruler itself also expanded x 2, then the table would measure 4 new (or x 2 expanded) feet.
INTERPOLATION ends

Now, don’t forget that the flatlander cannot perceive a dimension perpendicular to his sphere or, more correctly, to the surface of his sphere. He cannot perceive inside or outside that surface. (Leaving aside his time dimension). If we are super beings with that extra perception , we can say that his universe is expanding - the radius of his universe is increasing as well as the area of his universe. His universe has no edge. Hy is totally unware of expansion perpendicular to his surface.
His universe is limited to the surface of a sphere which has no edge.

If you, as a superbeing, can postulate that his universe as seen by us has an edge which is the two-dimensional surface of his world. I would not consider this assertion to be safe – others might. Please see Korzybski below.

Coming back to the flatlander, whilst we can postulate ‘an outside’ which allows expansion along the radius as well as expansion of the area (being his entire universe) he does not have the sensory equipment or understanding to operatementally.

If you now postulate that we are living in a closed universe, we have directly analogous limitations. There may be expansion of the Universe in some postulated dimension that we do not have the sensory equipment to understand, and some super being with extra senses may say that there is ‘an outside’ into which our Universe is impinging but these observations are not open to us and we cannot perceive an edge or an outside. It is meaningless to contrive some combination of words which endeavours to circumvent this.

It is a shame that General Semantics is not a compulsory subject in schools. Its catch phrase is The map not the territory. In this case it would be immediately visible to the GS student that to use words to describe an imaginary event is futile. The map (the words, the verbal description) IS not the territory (the reality). You cannot create a reality just by wrapping words around a verbal assertion.


QUESTION
"So why don't you think there is a boundary (edge) and a beyond for the universe?"


RESPONSE
Such a thing is unknowable to any being with the limitations imposed upon us by our physical makeup.
Any such enquiry is exacerbated by introducing assumptions of conditions unattainable in reality e.g., reaching an assumed edge of the Universe and possibly returning to it.

Mr. Franks.
I hope you will agree that I have taken a lot of time writing the above, and that it contains no criticism (explicit or implicit) of your good self. My motivation has been to explain and reply to your final stated question. I hope that I have succeeded in this and that you may have benefited from my efforts. Nevertheless, if I have not achieved that result, then I am sorry for my failure and I am willing to do my best to answer any further points you may wish to raise. The offer is of course open to any other members who may wish to join in.